Led array for illuminating cell well plates and automated rack system for handling the same

ABSTRACT

An assembly for promoting the growth of plant tissues that includes a plurality of plates each defining an array of wells wherein each of the wells contains a tissue sample. Support for the plates is provided by a rack having a plurality of vertically stacked shelves that may include one or more register depressions that urge the plates into predetermined positions. Light for the tissue samples is provided by a plurality of light-emitting diode arrays each mounted on a circuit board. Each circuit board is supported by a respective card edge connector of the rack so that the light-emitting diodes are in proximity to the plates supported on one of the shelves therebelow. Preferably, the light-emitting diode array corresponds to the well array supported in the registered position on the shelf therebelow so that each light-emitting diode is centered above a respective one of the wells.

FIELD OF THE INVENTION

The present invention is related to the use of artificial lightingsystems to promote plant growth, and more particularly, to the use oflighting systems to promote growth of plant tissue in cell well plates.

BACKGROUND OF THE INVENTION

In biological and biochemical screening systems that employ planttissue, it is important that the growth of the plant tissue be promoted.Growth of the plant tissue is affected by several factors which includethe amount and type of nutrients supplied to the tissue, the physicalsupport provided for the tissue, the temperature of the tissueenvironment and the amount of light delivered to the plant tissue. Withrespect to the availability of light, most screening systems employartificial light which can be controlled and is not subject to thevagaries of the weather. In addition, the screening systems typicallyemploy plates wherein each plate defines multiple wells. Each of thewells holds and isolates a separate tissue sample so as to avoidcontamination with other tissue samples and the environment.

Existing systems for promoting plant tissue growth typically employ arack, or “hotel,” having multiple shelves each holding a plurality ofthe multiple well plates. Above each shelf is a bank of incandescent orfluorescent lights providing illumination to the multi-well plates andthe tissue contained therein. The rack however, has a limited verticalstacking capacity as the lights must be kept a safe distance from theplant tissue to avoid excessive build-up of heat and because theincandescent and fluorescent lights are relatively bulky. Each shelf andlight bank combination requires about one foot of vertical space,limiting a normal room with eight feet high ceilings to seven or eightshelves. In addition, incandescent or fluorescent lights are not veryenergy efficient, requiring about 4.4 watts of power per multiple wellplate. Such large space and power requirements, coupled with costconstraints, tend to limit the density of the rack and the throughput ofplant tissue screening systems.

Therefore, it would be advantageous to have a system for promoting thegrowth of plant tissues that can supply sufficient light to plant tissuein multiple well plates while also allowing for an increase inthroughput of the screening operation. In particular, it would beadvantageous to have a system for promoting the growth of plant tissuesthat does not occupy an excessive amount of space, nor require the useof large amounts of power per plate.

BRIEF SUMMARY OF THE INVENTION

The present invention addresses the above needs and achieves otheradvantages by providing an assembly for promoting the growth of tissuesrequiring light to support proliferation. The assembly includes aplurality of plates each defining an array of wells wherein each of thewells contains one of the tissue samples and isolates its tissue samplefrom the other tissue samples. Support for the plates is provided by arack having a plurality of vertically stacked shelves spaced arelatively short distance away from each other. Each of the shelves mayinclude one or more register depressions that urge the plates restingthereon into predetermined positions. Light for the tissue samples isprovided by a plurality of light-emitting diode arrays wherein eacharray is mounted on a circuit board. In turn, each circuit board issupported by a respective card edge connector of the rack so that thelight-emitting diodes are in proximity to the plates supported on one ofthe shelves therebelow. Preferably, the light-emitting diode arraycorresponds to the well array supported in the registered position onthe shelf therebelow so that each light-emitting diode is centered abovea respective one of the wells.

In one embodiment, the present invention includes an assembly forpromoting the growth of tissue samples requiring light to supportproliferation. The assembly includes a plate defining therein aplurality of wells arranged in a well array. Each of the plurality ofwells is configured to support and isolate one of the tissue samples.Further, the assembly includes a plurality of light-emitting diodesarranged in a light-emitting diode array. The light-emitting diode arraycorresponds to the well array such that each of the light-emittingdiodes is positioned in proximity to a respective one of the wells so asto shine light into the respective one of the wells. Shining of lightinto the wells promotes proliferation of the tissue supported in thewells. Preferably, each of the light-emitting diodes is centered aboveits respective one of the wells. Further preferably, each of thelight-emitting diodes emits a white light and is an inch or less fromthe tissue sample in its respective one of the wells.

In another embodiment of the present invention, a plurality plates andlight-emitting diode arrays may be supported by a high-density rack. Therack includes a plurality of shelves vertically spaced from each otherwherein each of the shelves is configured to support at least one of theplurality of plates. Each of the light-emitting diode arrays issupported by the rack above a respective one of the shelves. Light fromthe light-emitting diodes shines into the wells of the plate supportedon the shelf below so as to promote tissue growth of the samplescontained in the plate.

Preferably, each of the light-emitting diode arrays supported by therack corresponds to the well array of the plate supported therebelowsuch that each of the light-emitting diodes is positioned above arespective one of the wells. In addition, the shelves of the rack caninclude register depressions which urge the plates disposed thereon intopredetermined positions such that each of the light-emitting diodes iscentered above its respective one of the wells. The rack may alsoinclude a plurality of card edge connectors that are each configured toreceive a circuit board in which the light-emitting diodes are embeddedto form a light-emitting diode array. The card edge connectors arepositioned to support the circuit boards, and the light-emitting diodesembedded therein, above the shelves supporting the plates. Preferably,the shelves are less than two inches apart allowing a relatively highdensity of plates to be held by a rack even when vertical storage spaceis limited.

In yet another embodiment, the high-density rack may be employed with amanipulation system for use in high-throughput screening. Themanipulation system includes a plate manipulator that has a range ofmotion. The rack is positioned so that the plates supported thereon arewithin the range of motion of the plate manipulator. The platemanipulator is then capable of supporting and removing each plate fromthe rack for automated processing, such as in a high-throughputsequencing operation.

The present invention has several advantages. The use of light-emittingdiodes that are less bulky and emit less heat than fluorescent andincandescent bulbs allows the shelves of the rack to be more closelystacked. More closely stacked shelves increases storage efficiency byreducing the amount of space needed to house an adequate supply oftissue samples. This is particularly important in high-throughputscreening operations where thousands of samples are needed on a dailybasis. In addition, more plates are accessible to automated platemanipulators, such as robotic arms, that have a limited range of motion.Matching and alignment of each of the wells with its own light-emittingdiode allows for calibration of the light beam spread and intensity foroptimal tissue growth. Further, the light emitting diodes use light moreefficiently and have lower power requirements for promoting tissuegrowth than fluorescent and incandescent bulbs, averaging about 1.3watts per standard 4 by 6 plate compared to 4.4 watts for fluorescentand incandescent systems.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 is a perspective view of a high throughput screening system ofone embodiment of the present invention;

FIG. 2 is a perspective view of a multiple well plate supported andcentered below a light-emitting diode array of another embodiment of thepresent invention;

FIG. 3 is perspective view of the rack shown in FIG. 1 including aplurality of vertically spaced shelves and card edge connectors forsupporting a plurality of the well plates and light-emitting diodearrays, respectively, shown in FIG. 2;

FIG. 4 is a rear elevation view of the rack of FIG. 3;

FIG. 5 is a perspective view of the light-emitting diode array of FIG.2;

FIG. 6 is a bottom plan view of the light-emitting diode array of FIG. 2including a circuit board for supporting light-emitting diodes; and

FIG. 7 is a perspective view of the rack of FIG. 3 with thelight-emitting diode arrays and multiple well plates of FIG. 2 installedtherein.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout.

In one embodiment, the present invention comprises a high throughputscreening system 10 which includes a robot 11 for the automatedmanipulation of multiple well plates 12 housed in a high-density rack orhotel 20 wherein each of the multiple well plates contains a pluralityof plant tissue samples 13, as shown in FIGS. 1 and 2. Above each of thewell plates is an array of light emitting diodes (LED's) 30 supported bya circuit board or card 31 that supply light to the plant tissue samples13 in the wells 14 defined in the well plates 12.

The high-density rack 20 includes a rectangular base 21, a pair of sidewalls 22, a plurality of shelves 23, a plurality of card edge connectors24 and a pair of connector supports 25, as shown in FIG. 3. The pair ofside walls 22 are horizontally spaced apart across the rectangular base21. More particularly, the side walls 22 are attached to, and extendvertically upwards from, the left and right sides of the rectangularbase 21. The shelves 23 are spaced from each other in the verticaldirection and extend between the side walls 22. The pair of side wallsare attached to the shelves so as to support the left and right edges ofeach of the shelves 23. Preferably, the shelves 23 are about 2 inchesapart, allowing more than 40 shelves to be stacked in a room with aceiling height of about 8 feet. In addition, each of the shelvespreferably defines at least one depression 26, ledge, edge or othermechanical or electrical device (such as a magnetic field) that urgesone of the plates 12 resting thereon into a registered position known bythe robot 11 for later retrieval and manipulation, as shown in FIG. 2.The rack 20 of the present invention should not be considered limited tothe aforedescribed embodiment. The rack could include any structure orassembly that provides supporting surfaces or supports at variousorientations and densities for a desired number of the plates 12 ortrays holding the plates. Preferably, however, the supporting surfacesshould have sufficient clearance for access by the robotic manipulator11, and some register device for urging the plates 12 into alignmentwith the corresponding array of LED's 30 and into a position known tothe robot for later retrieval.

The connector supports 25 each have an L-angle shape with one legaffixed to a respective one of the side walls 22 and the other legextending inwards toward the other one of the side walls and along theback of the rack 20, as shown in FIG. 4. The card edge connectors 24 areeach mounted to the connector supports 25 above a respective one of theshelves 23, and subjacent the next consecutive one of the shelves in thevertical direction. The card edge connectors 24 each define a horizontalslot sized to receive an edge of one of the circuit boards 31. Thehorizontal slots also ensure that the circuit boards 31, and hence thearrays of LED's 30, are correctly positioned above the shelves 23.

A pair of power leads 32 extend vertically along the backs of the cardedge connectors 24. The power leads 32 are electrically coupled to thehorizontal slot of each of the connectors by being soldered to adjacenttabs 33 on the backs of the card edge connectors 24. One of the powerleads 32 is attached to a tab on the top of the horizontal slot, whilethe other is attached to a tab on the bottom of the horizontal slot.Each of the circuit boards 31 is energized, sending power to its LED's,by insertion into its respective one of the card edge connectors 24. Aprotective shield 34 may be mounted over the power leads, extending in avertical direction along the back of the rack 20, so as to physicallyprotect the soldered connections as well as shield against interference.Although the card edge connectors 24 allow for easy installation andremoval of each array of LED's 30, the circuit boards 31 could also behard wired into the rack 20.

The number, dimensions and locations of the wells 14 in the well plates12 are tailored to be compatible with preexisting plate handlingequipment, such as the robot 11. For instance, the plate preferably has24 wells in an array of 4 by 6 (as shown in FIG. 2), or 48 wells in anarray of 6 by 8 to be compatible with most handling devices. Other welldensities could be used such as 6 wells, or 96 wells that are alsocompatible with conventional devices. However, nonstandard welldensities could also be used, such as a single well or a 1000 wells. Thewell plates 12 can also include transparent covers that further isolatethe tissue samples 13 enclosed therein while still allowing thetransmission of light from the LED's 30 to the tissue samples.

The LED's are preferably high-brightness, white LED's (Nichia Model No.NSPW-500BS available from Alpinetech of Irvine, Calif. U.S.A.) thatprovide sufficient light for tissue growth when the distance from thetissue 13 is less than one inch. The white LED's emit a relatively fullspectrum of light frequencies as compared to non-white LED's.Advantageously, the full spectra emission of the white LED's eliminatesthe problems of matching different LED's having different spectra to thediffering light sensitivities of various plant tissues so as to promotegrowth. In addition, all of the white LED's may be powered by a singlepower source.

Further preferably, the LED's 30 are in a twin-lead, 5 mm epoxy packageand are loaded in series into the printed circuit board 31 in the array,as shown in FIGS. 5 and 6. Alternatively, some or all of the LED's 30may also be individually wired, allowing individual control of each ofthe LED's. Each of the circuit boards 31 preferably has a contact at thetop and bottom of the board at its connecting edge positioned so as tocorrespond to the top and bottom tabs of each horizontal slot. Asmentioned above, the LED's need not be supported by a printed circuitboard, but could be hardwired into the desired array configurations andpositions necessary to shine sufficient light onto the well plates 12.

Preferably, the LED's 30 are spaced in each array so as to correspond tothe spacing of the wells 14 defined in each of the cell well plates 12.As a result, each of the LED's 30 are centered above a respective one ofthe wells 14 when the well plates 12 are properly positioned. Restated,each individual one of the LED's 30 is coupled, in a one-to-one ratio,with a respective one of the wells 14. Such a one-to-one coupling ispromoted by the white light emission of the LED's which eliminates theneed to have several different types of non-white LED's shining on eachplant tissue sample.

Proper positioning of the well plates 12 is ensured by the registerdepression 26 which urges its respective plate into a predeterminedposition on one of the shelves 23. For instance, the 4 by 6 array ofwells 14 of one of the plates 12 in its registered position correspondsto, and is centered under, the 4 by 6 array of LED's 30, as shown inFIGS. 2 and 7. Centering of one LED above each well allows the distancebetween the LED and tissue at the bottom of the well to be calibrated soas to provide an optimal amount of light beam spread and intensity topromote tissue growth. Preferably, beam spread for each LED is about a40 ° cone. The output intensity at full voltage and current is 5.6Candela (15-16 lumens/watt at 20 mA) with a 20 ° beam. The colortemperature is 6000 to 6500 Kelvin. Optimum spread angle and intensity,however, will vary depending in part upon the type of plant tissue andthe desired rate of growth. To achieve such variations, the LED's can becurrent limited using resistors to reduce output. Output can also bereduced by pulsing, shortening of duty cycles and/or reducing thevoltage. An increase in output can be achieved by increasing voltage andpulsing at a shorter duty cycle.

Arrays of LED's 30 corresponding to well plates 12 with standard arraysof 48 and 96 wells could also be used. In another alternative, the arrayof LED's 40 could be configured to correspond to a non-standard array ofwells, such as an array of 3 or 1000 irregularly spaced wells in a wellplate. In yet another alternative, the array of LED's 30 couldcorrespond to several of the well plates 12 disposed on one of theshelves 23. As an example, three of the 4 by 6 well plates 12 could besupported in registered positions on a single one of the shelves 23 andthe array of LED's 30 positioned thereabove is a 12 by 6 array.

In an example of the high-density stacking well plates 12 in the rack20, the low heat and small size of the LED's 30 allow the shelves 23 tobe vertically stacked two inches apart. A shelf size of 96 inches by 19inches would hold 90 standard 4 by 6 well plates 12 and at least 40shelves stacked vertically in 8 feet of vertical space (a typicalstorage room). A total of 3600 plates could then be stored and suppliedwith light in 101 cubic feet of volume. The number of tissue samples forsuch a configuration would be 86,400. In comparison, 505 cubic feetwould be required for the same number of samples when using fluorescentlighting with shelves spaced 1 foot apart and the same 4 by 6 wellplates. Further, the low power requirements of the LED's 30 reduce thepower required to light each plate from 4.4 watts for fluorescent lightsto 1.3 watts with the LED's. The lower power requirements are due inpart to the positioning of the LED's with respect to the wells 14 whichpromotes the efficient distribution of the light from the LED's. Inother words, more of the light generated by the LED's reaches the tissuethan in fluorescent lighting systems, requiring less light to begenerated overall.

During use of the high-throughput screening system 10, circuit boards 31containing arrays of LED's 30 are selected so as to correspond to thearrays of wells 14 of the plates 12 used in the screening operation. Thecircuit boards 31 are each attached to a respective one of the card edgeconnectors 24 by inserting the circuit board into the horizontal slot ofthe respective connector. Such insertion electrically couples the topand bottom contact areas on the board with the tabs 33 allowing power tobe supplied through the power leads 32. Once the boards 31 areenergized, the LED's 30 are switched on and begin supplying light.

The tissue samples 13 are loaded into the well plates 12 and freshliquid media is injected into the wells, preferably using an automatedsystem such as a GENESIS liquid handler manufactured by TECAN ofMannedorf, Switzerland. The well plates 12 containing the fresh planttissue samples 13 are gripped and positioned by the robot 11'smanipulator on the shelves 23 of the rack 20. As each of the well plates12 is positioned on its respective one of the shelves 23, the registerdepression 26 urges the well plate into a centered position below thecorresponding array of LED's 30. At intervals necessary for thescreening process, such as the need to replenish liquid nutrients,sample the liquid of one of the wells, remove some of the tissue samplesfrom the wells or replace one plate with another, the robot 11 accessesthe appropriate location on one of the shelves 23 and retrieves theplate from its position on the register depression 26.

The present invention has several advantages. The use of LED's 30 thatare less bulky and emit less heat than fluorescent and incandescentbulbs allows the shelves 23 of the rack 20 to be more closely stacked.More closely stacked shelves increases storage efficiency by reducingthe amount of spaced need to house an adequate supply of tissue samples13. This is particularly important in high-throughput screeningoperations where thousands of samples are needed on a daily basis. Inaddition, more plates are accessible to automated plate manipulators,such as robotic arms, that have a limited range of motion. Matching andalignment of each of the wells 14 with its own light-emitting diodeallows for calibration of the light beam spread and intensity foroptimal tissue growth. Further, the light emitting diodes 30 have lowerpower requirements than fluorescent and incandescent bulbs, averagingabout 1.3 watts per standard 4 by 6 plate compared to 4.4 watts forfluorescent and incandescent systems. White light emitting LED's 30 havethe advantage of emitting a full spectrum of frequencies and thereforebeing useable for many different types of plant tissue. In addition, theuse of white LED's promotes the one-to-one coupling of each LED with itsown cell well.

Many modifications and other embodiments of the invention will come tomind to one skilled in the art to which this invention pertains havingthe benefit of the teachings presented in the foregoing descriptions andthe associated drawings. Therefore, it is to be understood that theinvention is not to be limited to the specific embodiments disclosed andthat modifications and other embodiments are intended to be includedwithin the scope of the appended claims. Although specific terms areemployed herein, they are used in a generic and descriptive sense onlyand not for purposes of limitation.

That which is claimed:
 1. An assembly for promoting growth of tissuesamples requiring light to support proliferation, said assemblycomprising: a plate defining therein a plurality of wells arranged in awell array, each of the plurality of wells configured to support andisolate one of the tissue samples; and a plurality of light-emittingdiodes arranged in a light-emitting diode array corresponding to thewell array such that each of the light-emitting diodes is positionedopposite a respective one of the wells so as to shine light into therespective one of the wells and promote proliferation of the tissuesupported therein.
 2. An assembly of claim 1, wherein each of thelight-emitting diodes is centered above its respective one of the wells.3. An assembly of claim 2, wherein each of the light-emitting diodes isone inch or less from the tissue sample in its respective one of thewells.
 4. An assembly for promoting growth of tissue samples requiringlight to support proliferation, said assembly comprising: a plurality ofplates, each of the plates defining therein a plurality of wellsarranged in a well array, each of the plurality of wells configured tosupport and isolate one of the tissue samples; a rack including aplurality of supports spaced from each other and configured to supportat least one of the plates; and a plurality of light-emitting diodearray supported by the rack and cooperating respectively with thesupports so that light from the light-emitting diode array shines intothe wells of the plate and promotes growth of the tissue samplescontained therein, wherein each of the light-emitting diode arrayscomprises a plurality of light-emitting diodes arranged in an arraycorresponding to the well array of the plate such that each of the lightemitting diodes is positioned opposite a respective one of the wells. 5.An assembly of claim 4, wherein each of the supports include a registerdevice which urges the plate supported thereon into a register positionsuch that each of the light emitting diodes is centered opposite itsrespective one of the wells.
 6. An assembly of claim 5, wherein thesupport comprises a shelf and the register device is a registerdepression defined in the shelf.
 7. An assembly for promoting growth oftissue samples requiring light to support proliferation, said assemblycomprising; a plurality of plates, each of the plates defining therein aplurality of wells arranged in a well array, each of the plurality ofwells configured to support and isolate one of the tissue samples; arack including a plurality of supports spaced from each other andconfigured to support at least one of the plates; and a plurality oflight-emitting diode arrays supported by the rack and cooperatingrespectively with the supports so that light from the light-emittingdiode array shines into the wells of the plate and promotes growth ofthe tissue samples contained therein, wherein each of the light-emittingdiode arrays includes a circuit board and plurality of light-emittingdiodes carried by the circuit board and wherein the rack furtherincludes a plurality of card edge connectors each configured to receivethe circuit board of one of the light-emitting diode arrays and supportthe circuit board and light-emitting diodes above the respective one ofthe shelves.
 8. An assembly of claim 7, wherein the supports are spacedat most two inches apart.
 9. An assembly for housing a plurality ofplates and supplying light to a plurality of tissue samples, each of theplates defining therein a plurality of wells arranged in a well array,each of the plurality of wells supporting one of the tissue samples,said assembly comprising: a rack including a plurality of supportsspaced from each other; and a plurality of light-emitting diode arrayseach including a plurality of light-emitting diodes arranged in an arraycorresponding to the well array wherein each of the light-emitting diodearrays is supported by the rack opposite a respective one of the shelvesso that light from each of the light-emitting diodes shines into arespective one of the wells of the plate supported on the shelf.
 10. Anassembly of claim 9, wherein each of the shelves is configured to urgeat least one of the plurality of plates into a register position.
 11. Anassembly of claim 9, wherein each of the shelves defines a registerdepression shaped to urge the plate into a register position.
 12. Asystem for high-throughput processing of tissue samples requiring lightto support proliferation, said system comprising: a plurality of plates,each plate defining therein a plurality of wells arranged in a wellarray, each of the plurality of wells configured to isolate and hold oneof the tissue samples; a rack having a plurality of shelves verticallyspaced from each other, each of the shelves supporting at least one ofthe plates; a plurality of light-emitting diode arrays, each of thelight-emitting diode arrays positioned above a respective one of theplurality of shelves so as to shine light into the wells of the plates;and an automated manipulation system including at least one platemanipulator having a range of motion wherein the rack is positioned sothat the plates are within the range of motion of the plate manipulatorand wherein the plate manipulator is capable of supporting and removingeach plate from the rack for automated processing of the tissue samplescontained therein.
 13. A method of promoting growth of tissue samplescontained in multiple well plates having a plurality of wells arrangedin an array, wherein each well isolates and supports one of the tissuesamples, said method comprising: loading the wells of the well plateswith the tissue samples; positioning each well plate on a supportopposite an array of light-emitting diodes; shining light from thelight-emitting diodes into the respective wells of the well plates;removing each well plate from the support for additional downstreamprocessing; and urging the well plate into a registered position on thesupport until each light-emitting diode is centered opposite arespective one of the wells of the well plates.
 14. A method ofpromoting growth of tissue samples contained in multiple well plateshaving a plurality of wells arranged in an array, wherein each wellisolates and supports one of the tissue samples, said method comprising:loading the wells of the well plates with the tissue samples;positioning each well plate on a support opposite an array oflight-emitting diodes; shining light from the light-emitting diodes intothe respective wells of the well plates; and removing each well platefrom the support for additional downstream processing; wherein loading,positioning and supporting are performed by an automated system.
 15. Anassembly for promoting growth of tissue samples requiring light tosupport proliferation, said assembly comprising: a plurality of plates,each of the plates defining therein a plurality of wells arranged in awell array, each of the plurality of wells configured to support andisolate one of the tissue samples; a rack including a plurality ofshelves and a plurality of card edge connectors, said shelves verticallyspaced from each other with each shelf supporting at least one of theplates in a register depression which urges the plate into a registerposition and said card edge connectors each positioned above arespective one of the shelves; and a plurality of light-emitting diodearrays supported above the shelves by the card edge connectors, each ofthe light-emitting diode arrays including a plurality of light-emittingdiodes and a circuit board, said circuit board carrying thelight-emitting diodes in an array corresponding to the well array of theplate such that each of the light emitting diodes is positioned oppositea respective one of the wells and centered over its respective well whenthe plate is in the registered position.
 16. A method of promotinggrowth of tissue samples contained in multiple well plates having aplurality of wells arranged in an array, wherein each well isolates andsupports one of the tissue samples, said method comprising: loading thewells of the well plates with the tissue samples; automaticallypositioning each well plate on a support opposite an array oflight-emitting diodes; shining light from the light-emitting diodes intothe wells of the well plates; and automatically removing each well platefrom the support for additional downstream processing.
 17. A method ofclaim 16, wherein the loading the wells with tissue samples is performedautomatically.
 18. A method of claim 17, wherein automatically loading,positioning and removing are performed by robotic systems.
 19. A methodof promoting growth of tissue samples, said method comprising: loadingthe tissue samples into individual wells of a multiple well plate andpositioning the tissue samples opposite a respective one of the whitelight-emitting diodes; and shining white light on the tissue samplesusing the white light-emitting diodes.
 20. A method of promoting growthof tissue samples, said method comprising: loading the tissue samplesinto individual wells of a multiple well plate and positioning thetissue samples opposite a respective one of the white light-emittingdiodes; wherein the loading and positioning are performed automatically.